It is well-known in packaging technique that non-returnable packages for liquid-filled contents are manufactured by folding of a packing material consisting plastic-coated cardboard or plastic-coated paper. Such packing containers can be manufactured from blanks prepared and punched out in advance, which are provided with crease lines facilitating the fold-forming, tearing perforations and holes for pouring openings etc. The packages can also be manufactured from a web which is rolled off from a magazine roll, and in this case too, the packing material is usually provided with crease lines facilitating the fold-forming.
The prefabricated blanks generally are converted to containers by threading them onto a mandrel with the help of which, one end wall of the packing container is formed by folding in the lugs joined to the blank over the end surface of the mandrel whereupon they are fixed by means of heat and pressure in the folded-in position so as to form a tight and firm end wall. After the forming of the end wall, the container is pulled off the mandrel, is filled with the intended contents, and is closed by folding together portions of the packing material around the open end of the blank and sealing them to one another in a tight and firm seal. The plastic layers of the packing material are thus fused together along the overlapping portions with the help of the supplied heat and compression. The packages which are manufactured from a web which is rolled off from a magazine roll are often manufactured in such a manner that the web is converted to a tube by combining the longitudinal edge zones of the web with each other and sealing them to each other. The tube is then filled with the intended contents and is divided through repeated transverse seals to form packing units which are separated by means of cuts in the sealing zones. The separated packing units subsequently can be given the desired shape, usually parallelepipedic shape, through folding along the said prepared crease lines facilitating the fold-forming.
Packing containers which are manufactured in the above-mentioned manner should be provided appropriately with an opening arrangement so that the contents can be made accessible in a convenient manner to the user of the package. Such a manner which is generally known consists in that a punched-out hole is provided in the package wall, in particular along its upper plane end surface, this hold being covered on the inside of the package wall by a thin plastic film which either constitutes a part of the unbroken inside plastic layer of the package material or a specially applied plastic strip which is sealed around the said hole against the inside layer of the packing material. To make the contents accessible to the consumer of the package the thin plastic film has to be torn up which is done with the help of an outer cover sheet or so-called pull-tab which is general consists of a relatively rigid material, e.g. paper or aluminium foil or laminate thereof and which has a plastic-coated surface. By means of pressure and heat the plastic layer of the cover strip is made to fuse together with the plastic layer which is exposed in the prepared emptying hole. When the package is to be opened the cover strip is torn off, thus causing the thin plastic film in the opening hole to be torn up and removed, since it is joined through fusion to the plastic layer of the cover strip. These known opening arrangements in principle function well, but sometimes are difficult to realize, so that there is a need for alternative opening arrangements which are simpler to manufacture and cheaper to realize. The present invention is intended to provide an indication of such an opening arrangement whose characteristics are evident from the enclosed claims.